My addition: never bother debating belief. Beliefs are not thoughts or theories. They are seldom based on rational thought. You can debate the outward effects of those beliefs, like the legalities of gay marriage—but you cannot reasonably have a debate about the beliefs themselves.
Don’t mud wrestle with the pig, okay?
That post led me to this list of ethnic slurs. I’m amazed. I can’t even get through the Bs, but it’s fascinating in a rather sick way. I suppose it’s a good resource for writers.